[virt-tools-list] Virt-viewer Duplicating Display 1 On Display 2

[B. H.]

      I'm running a virtual Fedora 29 desktop on a Fedora 29 QEMU/KVM 
virtualization server.  I've configured my virtual desktop machine to 
have 2 displays, and I use virt-viewer to view & interact with this 
virtual desktop machine.
      This has generally worked, but lately virt-viewer has been 
duplicating guest display 1's output to guest display 2.  I've `lost` 
the output that should be going to guest display 2.

      At first I thought my window manager (Xfce) was screwing up by 
mirroring the displays, even though that option is disabled.  But then I 
noticed some things that convinced me the problem is not with Xfce:

1. When Xfce is configured to put the displays side-by-side (but
    it looks like they are mirrored) I cannot interact with the
    items displayed in guest display 2.  My mouse can only interact
    with desktop items on guest display 1.  They move on display 2 when
    I move them on display 1, but not the reverse.

    Conversely, if I change Xfce to truly mirror my displays, I
    can interact with desktop items with my mouse on either
    virt-viewer display.

2. When Xfce is configured to put the displays side-by-side (but
    it looks like they are mirrored) my workspace switcher shows
    a 2560x1024 desktop.  Conversely, if I change Xfce to truly mirror
    my displays, my workspace switcher shows a 1280x1024 desktop.

I believe the relevant output from "virsh dumpxml {virt_machine}" is:


     <channel type='spicevmc'>
       <target type='virtio' name='com.redhat.spice.0' state='connected'/>
       <alias name='channel0'/>
       <address type='virtio-serial' controller='0' bus='0' port='1'/>
     </channel>
     <channel type='unix'>
       <source mode='bind' 
path='/var/lib/libvirt/qemu/channel/target/domain-10-desktop/org.qemu.guest_agent.0'/>
       <target type='virtio' name='org.qemu.guest_agent.0' 
state='connected'/>
       <alias name='channel1'/>
       <address type='virtio-serial' controller='0' bus='0' port='2'/>
     </channel>

     <graphics type='spice' keymap='en-us'>
       <listen type='none'/>
       <image compression='off'/>
       <gl enable='no' 
rendernode='/dev/dri/by-path/pci-0000:01:00.0-render'/>
     </graphics>

     <video>
       <model type='virtio' heads='2' primary='yes'>
         <acceleration accel3d='yes'/>
       </model>
       <alias name='video0'/>
       <address type='pci' domain='0x0000' bus='0x00' slot='0x02' 
function='0x0'/>
     </video>


I'm at a loss on how to troubleshoot this.  Any suggestions, please?